"Japanese Prime Minister Shinzo Abe is a strong supporter of the [U.S.-Japan] alliance and has an ambitious agenda to increase the capability and flexibility of Japan's military. Japanese politics have stabilized after five years of divided rule, creating opportunity for more predictable alliance planning. However, constitutional, legal, fiscal, and political barriers exist to significantly expand defense cooperation. The most prominent debate involves relaxing or removing the self-imposed ban on Japanese forces participating in collective self-defense. Such measures face opposition from the public and from political parties. In addition, leaders in China and South Korea distrust Abe because of his past statements on Japanese actions in the World War II era. Suspicion from Beijing and Seoul also complicates Japan's efforts to expand its security role. Japan faces a complex security landscape in the region. North Korea's increased asymmetric capabilities pose a direct threat to Japan. A territorial dispute with China over a set of islets in the East China Sea raises the risk of military escalation, a scenario that could trigger U.S. treaty obligations to defend Japan. Japan has pursued security cooperation with others in the region, including Australia and several Southeast Asian countries."
CRS Report for Congress, RL33740